Split filament bundle at finish roll



- Sept; 16, 1958 B. T. SHARP 2,851,732

SPLIT FILAMENT BUNDLE AT FINISH ROLL Filed July 14. 1953 INVENTOiQ BENJAMIN T. SHARP BY x/w ATTORNEY United States Patent 1 2,851,732 SPLIT FILAMENT BUNDLE AT FINISH ROLL Benjamin T. Sharp, Chattanooga, Tenn., assignor to E. I.

du Pont de Nemours and Company, Wilmington, Del.,

a corporation of Delaware Application July 14, 1953, Serial No. 367,992 3 Claims. (Cl. 18-48) This invention relates to the production of filaments and fibers and more particularly to a process for improving the drawing characteristics of cold-drawable filaments of synthetic linear organic condensation polymers.

In the melt spinning of synthetic linear condensation polymers, particularly nylon, the molten polymer is extruded through a spinneret to form filaments. The filaments are quenched in a fluid medium, usually a stream of air, converged into a yarn bundle, and conditioned in an atmosphere of steam prior to the application of a lubricating composition or finish and winding up of the yarn. A lubricating composition, such as an aqueous emulsion of a low viscosity mineral oil, is applied principally to facilitate the subsequent so-called cold-drawing step disclosed in Babcock, U. S. 2,289,232.

It is an object of this invention to provide an improved process for the application of lubricating or treating compositions to multifilament yarns or tows. Another object is to improve the cold-drawing properties of synthetic linear organic polymeric yarns and filaments. Other objects will become apparent from the specification and claims.

The details of this invention will be more clearly apparent by reference to the following description when taken in connection with the accompanying illustration. In the figure, 1 represents a spinneret, and the filaments issuing therefrom are represented by 2. The filaments are passed through a four bundle convergence guide 3 and the individual bundles pick up lubricant at the four rolls 4. The lubricated bundles are recombined at the lower finish guide rolls into a single bundle which is then ready for drawing. The filament bundle is passed about feed roller 6 and then about a non-rotatable snubbing pin 7 from which it is passed around positively driven drawing roller 8 which rotates at a greater peripheral speed than roller 6. The drawn material is then passed through guide 9 and traverse guide 10 on to bobbin 11.

I have unexpectedly found that by separating the yarn bundle into a plurality of smaller filament bundles as it traverses the finish applicator and then recombining the filament bundles into the original yarn bundle, a yarn structure is produced which gives much improved performance in the drawing operation. The quality of the drawn product is also much improved. Another important advantage of the process of this invention is that higher spinning speeds can be employed to give greater productivity while still maintaining improved drawing performance and product quality. These points are illustrated in the following table which summarizes data obtained in the spinning of 3960 denier, 140 filament yarn from polyhexamethylene adipamide, and the 'subsequent drawing thereof at a ratio of 5.1 l.

As can be seen, the number of filament bundles at the finish applicator has a marked effect on the drawing performance and on the final yarn quality. It is further 2,851,732 Patented Sept. 16, 1958 seen that appropriate subdivision of the yarn bundle during treatment makes possible a significant increase in spinning speed, in addition to the improvement in the drawing operation and in the final yarn quality.

The finish applicator can be a roll, a fixed-porous medium, a spraying device, or any of the other known expedients of the art. If a roll is used, it may have a smooth surface, a mat surface, or it may be covered with a felt or with a layer of gauze suspended on it at the point of contact with the filament bundles. The plurality of filament bundles may all contact one finish applicator, or each filament bundle may contact a separate finish applicator, or modifications thereof as may be desirable.

The advantages of this invention are particularly apparent when spinning either yarns of relatively heavy denier or yarns containing a relatively large number of filaments. By separating the yarn bundle into a plurality of filament bundles of suitable small size when applying the lubricating composition, the performance in drawing is improved, the quality of the drawn yarn produced is improved, and the whole process can be speeded up as well. The number of smaller bundles into which the large bundle should be divided for application of the lubricating composition will depend upon the size of the original bundle. Most of the improvement in the above respects will be obtained by subdividing the yarn into smaller bundles containing less than 2000 denier and less than 70 filaments. 'The optimum depends upon the process speed. As noted, higher speeds require smaller bundles for the same improvement in drawing performance and yarn quality. While some further improvement in the above respects may be achieved by subdividing into bundles of less than 500 denier or less than 20 filaments, it will usually be economically desirable to operate in the range of between 500 and 2000 denier and between 20 and 70 filaments per bundle.

Since many different embodiments of the invention may be made without departing from the spirit and scope thereof, it is to be understood that the invention is not limited by the specific illustrations except to the extent defined in the following claims.

What is claimed is:

1. In the process of cold drawing a bundle of yarn spun from a synthetic linear condensation polymer, the improvement which comprises subdividing the bundle into smaller bundles, applying a lubrication composition to the smaller bundles, recombining the subdivided yarn bundles, and thereafter cold drawing the recombined bundle.

2. In the process of cold drawing a bundle of yarn from a synthetic linear condensation polymer, the improvement which comprises subdividing the bundle into smaller bundles of less than about 2,000 denier and containing up to about 70 filaments, applying a lubricating composition to the smaller bundles, recombining the subdivided yarn bundles and thereafter cold drawing the recombined bundle.

3. In the process of cold drawing a bundle of polyhexamethylene adipamide yarn, the improvement which comprises subdividing the bundle into smaller bundles of less than about 2,000 denier and containing no more than about 70 filaments, applying a lubricating composition to the smaller bundles, recombining the subdivided yarn bundles and thereafter cold drawing the recombined bundle.

References Cited in the file of this patent UNITED STATES PATENTS- 2,178,743 Dreyfus Nov. 7, 1939 2,289,232 Babcock July 7, 1942 2,657,433 Merriman Nov. 3, 1953 

1. IN THE PROCESS OF COLD DRAWING A BUNDLE OF YARN SPUN FROM A SYNTHETIC LINEAR CONDENSATION POLYMER, THE IMPROVEMENT WHICH COMPRISES SUBDIVIDING THE BUNDLE INTO SMALLER BUNDLES, APPLYING A LUBRICATION COMPOSITION TO THE SMALLER BUNDLES, RECOMBINING THE SUBDIVIDED YARN BUNDLES, AND THEREAFTER COLD DRAWING THE RECOMBINED BUNDLES. 